EFFECT OF ORAL CREATINE DURING ENERGY RESTRICTION IN ATHLETES

Abstract

365 Anaerobic performance and body protein have been shown to decrease with energy restriction. The purpose of this study was to determine whether oral creatine supplementation during energy restriction would affect performance or body composition changes. Sixteen males resistance trainers were tested with anaerobic cycle test (10 sprints of 6 s with 30 s between) before and after 4 d of energy restriction (18 kcal/kg formula) with daily creatine or placebo supplement. Body composition change was assessed with hydrostatic weighing and nitrogen balance. A control group did performance test and hydrostatic testing only and showed no changes over time. Muscle biopsies taken before and after energy restriction showed a 6 and 8% reduction in total creatine and creatine phosphate in P and a 16 and 17% increase in these metabolites in Cr. Cr and P similarly decreased their body weight (−2.5 kg), fat (−7.5 %), nitrogen (−654.6 mg/kg N), but Cr had less reduction in fat-free mass than P (−1.4% vs −2.4%) during energy restriction. CrS tended to perform 3.8% more and P 0.5% less total work during the post performance test (p <0.1). In conclusion, energy restriction in athletes caused a significant reduction in muscle creatine that was reversed by oral creatine. This enhancement of muscle metabolites was not reflected in a benefit on body fat or nitrogen balance but tended to improve anaerobic performance and reduce FFM loss during weight loss. Supported by grants from National Strength and Conditioning Association and Gatorade Sports Science Institute